As availability of high speed, high resolution galvanometric laser scanning systems has become more common and various laser processing applications for such systems have emerged, increased optical calibration performance of these systems has become increasingly demanding. Optical scanning devices typically include two generally orthogonal rotating mirrors, which require calibration in order to convert the mirror command angles into spatial target positions at a predetermined working distance or distances. High resolution applications can benefit from mirror actuator resolution of less than 10 μrad but such resolution can be difficult to achieve in practice due to poor calibration between the commanded beam position and actual beam position across a field of regard of the scanning system. Calibration problems are often compounded by errors associated with construction tolerances of the scanning systems and the position or orientation of an intended laser processing target after integration into the laser scanning system or application. Thus, a need remains for improved calibration methods that can achieve accuracy of a few μrad in laser scanning systems.